<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title th:text="${activity.title}">活动标题</title>
    <style>
        * {
            margin: 0;
            padding: 0
        }
    </style>
</head>
<body th:utext="${activity.body}">
活动内容
</body>
</html>